package cn.ethan.demo.design;

import java.util.concurrent.atomic.AtomicReference;

/**
 * CAS 「AtomicReference」 线程安全
 *
 * @author 张俊辉
 */
public class Singleton_06 {

    private static final AtomicReference<Singleton_06> INSTANCE = new AtomicReference<>();

    private static Singleton_06 instance;

    private Singleton_06() {}

    public static final Singleton_06 getInstance() {
        for (;;) {
            Singleton_06 instance = INSTANCE.get();
            if (null != instance) {
                return instance;
            }
            INSTANCE.compareAndSet(null, new Singleton_06());
            return INSTANCE.get();
        }
    }
}
